Results from this year's UK Cereal Pathogen Virulence Survey suggest that a new race of brown rust is present in the UK.
"Samples of wheat from previously resistant varieties, Robigus, Hyperion, Oakley and Timber were infected with brown rust," said Jim McVittie, HGCA Recommended Lists manager. "Clearly further work is required to confirm that these races can re-infect the varieties they were collected on, but the relatively large number of samples from Robigus does suggest the presence of a new race in the UK and seedling tests have confirmed that they can re-infect the variety."
The Survey is jointly funded by Defra and HGCA and tracks changes in cereal diseases that have the potential to overcome the resistance present in UK varieties. It concentrates on investigating samples from varieties with high resistance ratings on the HGCA Recommended Lists and aims to detect new, virulent pathotypes.
"The Survey provides vital early warnings of changes in pathogen virulence and how such changes might affect current varieties," said Jim McVittie.
Yellow rust virulence frequencies on wheat in 2006 were similar to the previous year with virulence for Robigus continuing to be common.
One yellow rust race collected in 2005 appears to combine virulence for Robigus with that for varieties such as Access, Mascot and Napier. This race also appears to be virulent on Timber but not Einstein.
"The virulence on Timber could affect its Recommended List rating for resistance to yellow rust," said Jim McVittie. "The failure to affect Einstein suggests that that variety carries an additional, currently unidentified, resistance factor."
Samples collected from Robigus confirmed the presence of races of mildew which can infect the variety. These races are now being found in Recommended Lists trials and the rating of the variety has been revised to 7.
"Eight samples were also collected from Timber suggesting a new race on that variety," said Jim McVittie. "This race has yet to be detected in Recommended Lists trials."
The Survey celebrates 40 years of existence this year. A new 5 year contract will ensure that all trials will be carried out by NIAB in Cambridge, which will allow the Survey to be flexible and react quickly to changes in virulence.
Release date: 11 May 2007
The full results of the survey can be found on the UKCPVS page of the HGCA website at http://www.hgca.com/content.output/56/56/Crop%20Research/Crop%20Research/UK%20Cereal%20Pathogen%20Virulence%20Survey.mspx
For further information contact:
Graham Jellis, HGCA Research Director, 020 7520 3932 graham.jellis@hgca.com
Madeleine Archer, HGCA Press Officer, 020 7520 3926 madeleine.archer@hgca.com | 
